JP3416634B2 - Dynamic damper - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic damper, and more particularly to a dynamic damper which is mounted on a tennis racket to improve the shock and vibration characteristics generated at the time of hitting a ball.

[0002]

2. Description of the Related Art A dynamic damper (vibration suppressing material), which is a viscoelastic material combined with a mass-adding material, is commonly used to reduce or mitigate shocks and vibrations that occur when using sports ball hitting tools and tools. Often used. In particular, in the case of a tennis racket, Japanese Patent Publication No. 52-13455 and Japanese Unexamined Patent Publication No. 52
No. 156031 and Japanese Patent Laid-Open No. 4-263876, a tennis racket is provided with a vibration suppressing member consisting of a cantilever type damper in which a load member is fixed via an elastic member, and resonates with the vibration of the racket frame. Some have been proposed that dampen vibrations. That is, Japanese Patent Publication No. 52
In No. -13455, as shown in FIG. 23, a cantilever type damper 6 made of an elongated elastic member in which a base end of a steel wire 6b having a weight 6a attached to a tip end thereof is embedded in a frame is attached to an end of a grip 5 of a tennis racket. Is attached.
In Japanese Patent Laid-Open No. 52-156031, as shown in FIG. 24, a base portion 3a is fixed to a throat portion 4 of a tennis racket, a main body 3c is connected from the base portion 3a through a neck portion 3b, and the main body 3c is vibrated. I am trying. Japanese Patent Laid-Open No. Hei 4
In No. 263876, as shown in FIG. 25, the load member 4b is fixed to the grip end 5a of the tennis racket via the elastic body 4a.

All of the above-mentioned conventionally proposed tennis rackets mainly suppress the primary vibration in the out-of-plane direction of the racket frame (the direction perpendicular to the face surface of the racket frame, the thickness direction of the racket frame). For that purpose, the shape and the fixed position of the vibration suppressing member are set. That is, the load material is fixed to the tip of one elastic material whose one end is fixed to the racket frame, and energy is consumed by vibrating at the same frequency as the racket frame, and vibration and impact of the racket frame are prevented. Suppresses and allows fast decay.

However, the vibrations of the tennis racket, which are mainly felt by humans, are not only the vibrations in the out-of-plane direction but also the in-plane direction (the direction parallel to the face surface of the racket frame and the width direction of the racket frame). . In addition, the impact due to the rotation of the grip when the ball is hit off the center axis of the frame is very uncomfortable.

Conventionally, the above-mentioned in-plane vibration has not been considered so much, but in particular, the vibration of the gut tension portion in the in-plane direction is generated in the gut tension portion by deformation of the gut directly hit by the ball. Yes, it has a great influence on the player's sensibility evaluation (feeling), that is, whether or not the shot feeling is good.

For example, it is said that a so-called decarrage, which has a large face area (area of the gut stretched portion), which has been developed to improve flight, has more unpleasant vibrations than a racket having a small face area. This is because the face area is large, so that the face is easily bent in the in-plane direction, that is, the vibration of the gut tension portion in the in-plane direction is large. From these, it is considered that it is particularly important for a tennis racket such as a deraquette designed to improve the flight, in addition to the vibration in the out-of-plane direction, the vibration in the in-plane direction as well.

Therefore, the present applicant has filed Japanese Patent Application No. 10-3408.
No. 36 proposes a vibration suppressing material (dynamic damper) having a U-shaped cross section. According to the vibration suppressing member having this shape, in addition to the vibration in the out-of-plane direction, the vibration in the in-plane direction can be suppressed well.

[0008]

However, in the above vibration suppressing member having a U-shaped cross section, it is possible to improve the vibration damping property in the in-plane direction in addition to the out-of-plane direction.
The effect on the out-of-plane vibration of the racket frame may be smaller than the effect on the in-plane vibration.
There is still room for improvement in order to further improve vibration damping.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a dynamic damper which is excellent in the action of mitigating / reducing shock and vibration.

[0010]

In order to solve the above-mentioned problems, the present invention is a dynamic damper which is integrally laminated with a viscoelastic material and a mass-adding material and which is attached to a racket. And a vertical frame portion on both sides of the horizontal frame portion in a lattice shape, the horizontal frame portion and the vertical frame portion are integrally provided or provided separately by joining, and the horizontal frame portion is a racket. The dynamic damper is characterized in that it is attached to at least one side in the thickness direction of the racket, and the vertical frame portion is attached to both sides in the width direction of the racket.

The thickness direction of the racket means a direction perpendicular to the gut surface, and the width direction means a horizontal direction parallel to the gut surface.

The horizontal frame portion is bent in a U shape, the tips of both side bending portions are integrally or joined to the vertical frame portion, and both side bending portions of the horizontal frame portion are attached to both sides in the width direction of the racket. . Further, it is preferable that there are two or more horizontal frame portions, and the horizontal frame portions are arranged so as to sandwich the gut insertion hole. Therefore, the dynamic damper has a square shape when there are two horizontal frames, a "day" shape when there are three horizontal frames, and an "eye" shape when there are four horizontal frames. Become.

That is, the lattice-shaped dynamic damper of the present invention has a shape in which a strip-shaped vertical frame portion is integrally or separately provided on a U-shaped horizontal frame portion.
In this way, the horizontal frame portion and the vertical frame portion are continuously and integrally provided and arranged in a grid pattern. Therefore, in the racket to which the dynamic damper is attached, the vertical frame portion is out of the plane of the racket frame. While resonating mainly with sway,
The horizontal frame portion resonates mainly with in-plane vibration of the racket frame, and vibrations in both in-plane and out-of-plane directions can be effectively suppressed. In this way, the lattice-like arrangement improves the vibration damping property in all directions, so that the vibration / impact can be reduced.

Further, when integrally formed in a lattice shape,
Since the vertical frame portion and the horizontal frame portion are integrally connected, the whole lattice resonates together with the in-plane vibration, so that the effect of suppressing the in-plane vibration is more excellent. That is, when integrally molded in a lattice shape, the weight of the entire dynamic damper contributes to vibration suppression in the in-plane direction and the out-of-plane direction, so that the vertical frame part and the horizontal frame part are individually in-plane and out-of-plane directions. Since the effect of suppressing vibration is greater than that of contributing to suppressing vibration, the vibration damping property is superior.

The ratio of the length (L2) of the vertical frame portion to the length (L1) of the horizontal frame portion (L2 / L1: or less, also referred to as aspect ratio) is 0.3 or more and 1.0 or less. Is less than 0.3, the portion that vibrates the dynamic damper in the out-of-plane direction becomes too small, and the effect in the out-of-plane direction becomes small. On the other hand, if it is greater than 1.0. This is because the weight of the entire dynamic damper increases and it becomes difficult for the racket to swing, and the vibration of the entire dynamic damper, particularly the vibration in the in-plane direction, is less likely to occur. This aspect ratio is more preferably 0.6 or more and 0.9 or less. The lengths of the horizontal frame portion and the vertical frame portion are the lengths of the horizontal frame portion and the vertical frame portion at the center in the thickness direction, respectively.

The range of the aspect ratio is such that the length direction of the vertical frame portion coincides with the longitudinal direction of the racket frame (the length direction of the horizontal frame portion is the direction perpendicular to the face). When attached to a tennis racket, it exhibits particularly excellent vibration damping properties.

The width of each part of the viscoelastic material is 4 mm or more 8
mm or less. This is because if the thickness is less than 4 mm, the adhesion to a mounted object such as a racket frame will deteriorate.
This is because if it is larger than mm, the weight of the dynamic damper becomes heavy, the vibration of the dynamic damper itself is suppressed, and the vibration damping effect of the racket frame becomes small.
More preferably, the width is 4 mm or more and 6 mm or less.

The thickness of each part of the viscoelastic material is 2.5 mm.
The above is 5.5 mm or less. This is because if the thickness of the viscoelastic material is less than 2.5 mm, the dynamic damper is less likely to vibrate and the vibration suppressing effect of the dynamic damper is impaired. Further, the thickness of the viscoelastic material is 5.
This is because if it is larger than 5 mm, it becomes a hindrance when mounting and the appearance becomes bad. The more preferable thickness of the viscoelastic material is 3 mm or more and 5 mm or less.

The total weight of the dynamic damper is 8 g.
It is above 23 g. This is because if it is less than 8 g, the vibration suppressing performance is not sufficient, and if it is heavier than 23 g, the operability of the mounted object such as a tennis racket is deteriorated.

The viscoelastic material has a complex elastic modulus at 20 ° C. and 10 Hz of 0.3 MPa or more and 1.5 MPa or less. This is because the complex elastic modulus is less than 0.3 MPa, and there is no solid material suitable for mounting on a mounted object such as a tennis racket. On the other hand, the complex elastic modulus is 1.
This is because if it is larger than 5 MPa, the dynamic damper having the shape of the present invention cannot match the frequency of the dynamic damper with the frequency of the mounted object such as a tennis racket.

The mass addition material has a complex elastic modulus of 100 MPa or more and 800 MPa or less at 20 ° C. and 10 Hz. The mass-adding material having a complex elastic modulus of 100 MPa or more and 800 MPa or less is not as soft as a viscoelastic material, but is softer and more elastic than a hard metal. In this way, the mass addition material having a certain degree of softness and the dynamic damper of the present invention made of a very soft viscoelastic material,
Even if it is hit by a person, it does not hurt or hurt your hands, and there is no concern that safety will decrease. Further, if the mass addition material is soft, even if the viscoelastic material is integrated with the mass addition material by bonding the surfaces together, the viscoelastic material is not strongly bound by the mass addition material, and Since not only the portion but also the portion of the mass addition material can be deformed, a dynamic movement occurs in the entire dynamic damper, a sufficient resonance phenomenon occurs, and the effect of mitigating and reducing impact vibration can be sufficiently exerted.

If the mass-applying material is a hard and rigid body, only the viscoelastic material can be deformed. If the viscoelastic material is integrated with the mass-applying material by bonding the surfaces together, the viscoelastic material is Since it is strongly restrained by the additional material, dynamic movement does not occur in the entire dynamic damper and a sufficient resonance phenomenon does not occur, so that the effect of mitigating and reducing impact vibration cannot be fully exerted.

In the dynamic damper of the present invention, if the complex elastic modulus of the mass-adding material is less than 100 MPa, the specific gravity (weight) sufficient to give a sufficient mass-adding effect cannot be secured, and if it exceeds 800 MPa. , Can't have the required softness. Further, if the complex elastic modulus of the mass-adding material is 300 MPa or less, the softness of the mass-adding material becomes more sufficient, and the effect of mitigating and reducing impact vibration can be fully exerted. Is more preferable.

The complex elastic moduli of the viscoelastic material and the mass addition material in the present invention are measured under the following conditions. Measuring instrument used: Viscoelastic spectrum made by Rheology Co., Ltd. DVE-V4FT Rheospectler Initial load: 250 g Frequency: 10 Hz Displacement amplitude: 5 μm Direction: Pulling temperature: 20 ° C. Distance between chucks: 30 mm

The total thickness of the dynamic damper including the viscoelastic material and the mass addition material is 3.0 mm or more and 7.0 m.
It is preferably m or less. This is because if the total thickness of the dynamic damper is less than 3.0 mm, it becomes difficult for the dynamic damper to vibrate, and the vibration suppressing effect of the dynamic damper is impaired. Further, if the thickness of the entire dynamic damper is larger than 7.0 mm, it will be an obstacle when mounting and the appearance will be poor.

The mass-adding material of the dynamic damper of the present invention may be made of metal, but preferably contains a high specific gravity metal powder and a polymeric material such as resin, rubber or elastomer as a main component and a high specific gravity metal powder. Examples thereof include those made of a mixture kneaded and dispersed in a polymer material. Also,
As the viscoelastic material of the dynamic damper of the present invention, when a polymer material is used as the mass addition material, a polymer material which is the same as or close to the polymer material is used. In addition to the polymer material and the high specific gravity metal powder, an oil for adjusting the elastic modulus and / or an oil for improving the moldability may be added, or a pigment for coloring may be added.

The metal of the high specific gravity metal powder is not limited to a specific metal, but one having a specific gravity of 5 or more and 25 or less at 20 ° C. is preferably used. This is because when the specific gravity is less than 5, the volume becomes too large when an attempt is made to have a sufficient mass adding action as a mass adding material.
If it exceeds 5, the corresponding metal is a rare metal and is expensive or difficult to obtain. Specific metals include iron (specific gravity 7.86), copper (specific gravity 8.92), and lead (specific gravity 1
1.3), nickel (specific gravity 8.85), zinc (specific gravity 7.
14), gold (specific gravity 19.3), platinum (specific gravity 21.4),
Osmium (specific gravity 22.6), iridium (specific gravity 22.
4), tantalum (specific gravity 16.7), silver (specific gravity 10.4)
9), chrome (specific gravity 7.19), brass (specific gravity 8.5),
Tungsten (specific gravity: 19.3) and the like can be mentioned. However, since lead is harmful and gold and silver are expensive, tungsten, copper, nickel and alloys thereof are preferable.
Further, it is preferable that the high specific gravity metal powder is subjected to surface treatment (for example, silane coupling coating) with a coupling agent in order to improve the adhesiveness with the polymer material.

The particle size of the high specific gravity metal powder is 1 μm or more and 25
The range of 0 μm or less is preferably used. If the particle size is less than 1 μm, the particles are likely to scatter or aggregate, and it becomes difficult to disperse during kneading. If the particle size exceeds 250 μm, the particles become large, and it is difficult to prepare a thin mass addition material.

Examples of the resin for polymer materials used as the viscoelastic material and the mass addition material include polyamide resin, polyester resin, urethane resin, polycarbonate resin, ABS resin, polyvinyl chloride resin. ,
Thermoplastic resin such as polyacetate resin, polyethylene resin, polyvinyl acetate resin, polyimide resin, epoxy resin, unsaturated polyester resin, phenol resin, melamine resin, urea resin, diallyl phthalate resin Examples of the resin include thermosetting resins such as resins, polyurethane resins, and polyimide resins. From the viewpoint of moldability and recyclability, a thermoplastic resin is preferable to a thermosetting resin.

Further, since the thermoplastic elastomer is softer than the thermoplastic resin, it is easy to adjust the frequency, and it has rubber elasticity and little plastic deformation and also has recyclability, so that it is a polymer for mass-adding material. Particularly preferred as a material. That is, in the case of a mixture in which the high specific gravity metal powder and the thermoplastic elastomer are the main components and the high specific gravity metal powder is dispersed in the thermoplastic elastomer, a mass addition material having an appropriate complex elastic modulus is easily obtained.

The thermoplastic elastomer is not particularly limited, but styrene type, olefin type, urethane type,
Ester type etc. are mentioned. As commercially available thermoplastic elastomers, Kuraray Plastic's Septon Compound, Kuraray's High Blur, Septon,
Elastage manufactured by Tosoh Corporation, neat polymer manufactured by Kanegafuchi Chemical Co., Ltd., Nubelan manufactured by Teijin, Aron Kasei Co., Ltd.
Elastomer AR manufactured by Shell Japan, Kraton D, Kraton G manufactured by Shell Japan Co., Ltd., Pelprene manufactured by Toyobo Co., Ltd., Tuftec manufactured by Asahi Kasei Corporation, Sumitomo Bakelite Co., Ltd.
Sumiflex, Moldex, Spydex, Sumicon RM, Mitsubishi Kasei Co., Ltd. Thermorun, Lavalon,
Sumitomo Chemical Co., Ltd. Sumitomo TPE, Sumitomo TPE-SB, Daicel Chemical Co., Ltd. Epofriend, Nippon Zeon Co., Ltd. Quintac, AES Japan Co., Ltd. Santoprene, Trefusin, DSM Surlink, etc. Is mentioned.

As the viscoelastic material of the dynamic damper of the present invention, when a polymer material is used as the mass addition material as described above, a polymer material which is the same as or close to the polymer material of the mass addition material is used. Preferably. In the case of a viscoelastic material, it may be a foam. If they are the same or similar polymer materials, their melting points are close, so it is possible to manufacture dynamic dampers by heating the materials of viscoelastic material and mass-adding material in one mold, melting and adhering them, and integrally molding them. It will be possible.

As the rubber for the polymer material of the viscoelastic material and the mass addition material, natural rubber (NR), isoprene rubber (I)
R), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), carboxylated nitrile rubber, butyl rubber (IIR), halogenated butyl rubber (X-IIR), Ethylene-propylene rubber (E
PM), ethylene-propylene-diene rubber (EPD
M), ethylene-vinyl acetate rubber (EVA), acrylic rubber (ACM, ANM) ethylene-acrylic rubber, chlorosulfonated polyethylene (CSM), polyethylene chloride (CM), epichlorohydrin rubber (CO), urethane rubber, silicone rubber, Fluorine-based rubber may be used. When the viscoelastic material and the mass-adding material are similar rubber materials, vulcanization and adhesion are easy to perform, which is more preferable because it is suitable for integral molding. Ethylene-propylene-diene rubber (EPDM) and silicone rubber are good in terms of weather resistance, and butyl rubber (IIR) in terms of excellent vibration absorption.
Is good.

The dynamic damper of the present invention may be formed into a desired dynamic damper shape by laminating the materials of the viscoelastic material and the mass-adding material into a die and molding them into a single flat sheet. Then, it may be punched with a punching blade or the like to be molded into a desired shape.

The above-mentioned dynamic damper is attached to the tennis racket. Specifically, a dynamic damper is attached to at least a part of the gut tension portion and / or the throat portion surrounding the face surface of the racket frame, and the dynamic damper is formed by integrally laminating a viscoelastic material and a mass addition material. The racket frame is attached to at least one surface in the thickness direction and both surfaces in the width direction, and the vibration damping ratios of the out-of-plane secondary and in-plane tertiary of the racket frame are both 1% or more.

The above-mentioned out-of-plane quadratic and in-plane ternary vibration damping ratios mean that the tennis racket has an out-of-plane quadratic mode and an in-plane ternary at each frequency of the quadratic in-plane and the in-plane ternary It is the damping ratio of each vibration when each mode is deformed. When the value of the vibration damping ratio is large (1% or more), the vibration generated at the time of hitting the ball is excellent in damping property, and the player does not feel uncomfortable vibration. When a dynamic damper having a part that resonates mainly with the out-of-plane direction and resonates with the in-plane direction is installed, vibration in both directions is effectively suppressed in this way, and shock vibration is prevented. It can be sufficiently relaxed and reduced.

Since the dynamic damper has a structure in which a mass addition material is laminated on a layer of viscoelastic material and is attached to the racket frame via the viscoelastic material, the viscoelasticity of the dynamic damper against vibration of the racket. The material vibrates largely, vibrates the mass addition material, and the vibration of this dynamic damper vibrates earlier than the vibration of the racket frame, which conventionally consumes the energy to vibrate the racket frame, thereby rapidly vibrating the racket frame. Can be attenuated. As a result, the shock and vibration applied to the player's hand can be greatly reduced.

The dynamic damper of the present invention, in the gut tension portion surrounding the face surface of the racket frame,
If the top position is 12 o'clock when the face is viewed as a clock face, an angle range of ± 15 degrees centered on the 3 o'clock position and 9
A tennis racket equipped with a dynamic damper that is mounted in at least a part of an angle range of ± 15 degrees centered on the hour position can be used in in-plane and out-of-plane directions without adversely affecting the operability of the tennis racket. Both vibrations can be suppressed more efficiently.

In the dynamic damper of the present invention, as described above, the vertical frame portion resonates mainly with the out-of-plane vibration, while the horizontal frame portion resonates mainly with the in-plane vibration. Can be effectively suppressed, and shock vibration can be sufficiently relaxed and reduced. The tennis racket equipped with this dynamic damper is out-of-plane secondary and in-plane 3
The following vibration damping ratios (hereinafter, also referred to as damping ratios) are both 1% or more, and the vibration damping properties are very excellent. Moreover, since the weight of the entire dynamic damper is appropriate for the tennis racket, the ease of swinging (good operability) can be maintained.

Particularly, the positions of the racket frame at 3 o'clock and 9 o'clock are the maximum vibration width position of the in-plane vibration and the maximum vibration width position of the out-of-plane secondary vibration. It is optimal to mount at the 3 o'clock and 9 o'clock positions from the viewpoint of both in-plane and out-of-plane vibration suppression and rotation suppression.

Further, since the mass is added to a portion where the width of the gut stretched portion is large, the moment of inertia around the grip becomes large and the racket is prevented from rotating when the ball hits other than the center of the face surface. This effect can be achieved, and the burden on the elbows of the tennis racket user can be reduced.

Further, the dynamic damper of the present invention is
As described above, it is preferable that the lengthwise direction of the vertical frame portion is the longitudinal direction of the racket frame (the direction horizontal to the face surface of the racket frame) and that the racket frame is mounted on the gut tension portion.

Further, the dynamic damper of the present invention is
In the gut tension section that surrounds the face surface of the racket frame, assuming that the top position is 12 o'clock with the face surface as the clock face, the angle range of ± 15 degrees around the 4 o'clock position and the 8 o'clock position is the center. A tennis racket equipped with a dynamic damper that is installed in at least a part of an angle range of ± 15 degrees is more efficient in both in-plane and out-of-plane vibration without adversely affecting the operability of the tennis racket. Can be suppressed. Specifically, since the balance of the racket can be adjusted to the hand side, the racket can be easily swung.

Further, the dynamic damper of the present invention is such that, in the gut tension portion surrounding the face surface of the racket frame, the top position is 12 when the face surface is regarded as the clock face.
If it is time, the tennis racket equipped with the dynamic damper mounted in at least a part of the ± 15 ° angle range centered on the 5 o'clock position and the ± 15 ° angle range centered on the 7 o'clock position is Both in-plane and out-of-plane vibrations can be suppressed more efficiently without adversely affecting the operability of the tennis racket. Specifically, since the balance of the racket can be adjusted to the hand side, the racket can be easily swung.

The dynamic damper of the present invention is
From the standpoint of balance, it is preferable that the racket frame is mounted at symmetrical positions on the racket frame, but is not limited thereto. Further, the number of racket frames is not limited to one on each side, but a plurality of racket frames may be attached. Further, it is preferable that the racket frame has a recess at the dynamic damper mounting position.

[0046]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a dynamic damper according to a first embodiment of the present invention.

The dynamic damper 10 is attached to a tennis racket and, as shown in FIG. 1, is composed of a sheet in which a mass addition material 11 and a viscoelastic material 12 are laminated. Three U-shaped lateral frame portions 13 obtained by bending this sheet into a U-shaped cross-section are located at substantially parallel intervals. Two vertical frame portions 14 made of the above-described sheet are parallel to each other at both ends of these horizontal frame portions. Both are continuously and integrally coupled to each other to form the dynamic damper 10 in a lattice shape.

The dynamic damper 10 is shown in FIG.
(B) As shown in (C), the length L1 of the lateral frame portion 13
Ratio L of the length L2 of the vertical frame portion 14 (the length in the direction horizontal to the face surface when attached to the racket) to (the length in the direction perpendicular to the face surface when attached to the racket)
2 / L1 (aspect ratio) is 0.3 or more and 1.0 or less. The width of each part of the viscoelastic material 12 is 4 mm or more and 8 mm or less,
The thickness of each part is 2.5 mm or more and 5.5 mm or less.
The total weight of the dynamic damper 10 is 8 g or more 23
It is set to g or less.

The mass addition material 11 is a mixture of a high specific gravity metal powder and a thermoplastic elastomer or a thermoplastic resin as a main component, and the high specific gravity metal powder is dispersed in the thermoplastic elastomer or the thermoplastic resin at 20 ° C. The complex elastic modulus at 10 Hz is 100 MPa or more and 800 MPa or less, and the viscoelastic material 12 has a complex elastic modulus at 20 ° C. and 10 Hz of 0.5 MPa or more and 1.5 MPa or less.

In the dynamic damper 10, as shown in FIG. 2, the central portion of the U-shaped horizontal frame portion 13 is arranged on the inner surface in the thickness direction of the racket frame f, and both side bending portions of the horizontal frame portion 13 are racket. Arranged on both sides of the frame f in the width direction,
A tennis racket in which the strip-shaped vertical frame portions 14 are arranged on both sides in the width direction of the racket frame f, and the surface on the side of the viscoelastic material 12 is in contact with the surface of the inside of the racket frame f (the side on which the gut g is stretched). Is attached to. The three horizontal frame portions 13 are arranged in parallel with each other with the gut insertion hole interposed therebetween and attached.

The dynamic damper 10 is shown in FIG.
As shown in, the face surface S of the racket frame f
1 at the 3 o'clock position and 9 o'clock position of the gut tension section 1 surrounding the
Each piece is fixed with an adhesive. In this way, by mounting the dynamic damper 10, both the out-of-plane secondary and in-plane tertiary damping ratios of the racket frame are 1
It is set to be over%.

In the dynamic damper 10 of the first embodiment described above, two strip-shaped vertical frame portions 14 are perpendicular to each of the three U-shaped horizontal frame portions 13 which are bent in a U-shaped cross section.
Since they are continuously and integrally coupled and arranged in a lattice, not only the out-of-plane impact vibration but also the in-plane impact vibration can be sufficiently relaxed and reduced.

The dynamic damper of the present invention can be manufactured as follows. First, the high specific gravity metal powder and the thermoplastic elastomer are sufficiently kneaded in a suitable blend using a mill, and then heated and pressed by a hot press to form a sheet, which is then cut out to a required size to obtain a mixture for a mass addition material. Get the piece. Next, the obtained mixture piece is set in a die for a dynamic damper having a desired shape, charged with thermoplastic elastomer pellets for a viscoelastic material, and then heated and pressed to obtain a dynamic damper. Alternatively, the kneaded product of the mill may be crushed, charged into the cavity of the mass-adding material mold, and press-molded under heating to set the mass-adding material in the dynamic damper mold.

As described above, when the dynamic damper is attached so that the strip-shaped vertical frame portions are located in parallel with each other in the longitudinal direction of the racket frame, it contributes to both the in-plane direction and the out-of-plane direction. preferable.

In the first embodiment, the racket frame 3
The dynamic dampers are attached at the 9 o'clock position and the 9 o'clock position, but as shown in FIG. 5, in the gut tension portion 1 surrounding the face surface S of the racket frame f, the top position is set with the face surface S viewed as a watch face. Assuming 12:00, an angle range of ± 15 degrees centered on the 3 o'clock position, an angle range of ± 15 degrees centered on the 9 o'clock position, an angle range of ± 15 degrees centered on the 4 o'clock position and an 8 o'clock position ± 15 around
The angle damping range of the tennis racket TR is particularly excellent when it is attached to at least a part of the angle range of ± 15 degrees around the 5 o'clock position and the angle range of ± 15 degrees around the 7 o'clock position. .

Specifically, in the gut tension portion 1 surrounding the face surface S of the racket frame f, if the top position is 12 o'clock when the face surface S is viewed as a clock face, as shown in FIG. The dynamic damper 10 may be mounted at the position and the 8 o'clock position. Also, as shown in FIG.
Dynamic damper 10 at 5 and 7 o'clock
May be attached.

The composition of the racket frame includes, but is not limited to, fiber reinforced resin, metal, etc., and is applicable to all other types of racket frames.

Hereinafter, Examples 1 to 7 and Comparative Examples 1 to 7 of a tennis racket equipped with the dynamic damper of the present invention.
Will be described in detail. Note that the tennis racket has the same shape, length, and face area in the examples and the comparative examples.
The total length was 699 mm, the thickness of the gut tension portion surrounding the face surface S was 24 mm, and the thickness of the throat portion was 21 mm.
Gut stretched 12mm wide, throat 14m wide
m. The part where the dynamic damper is mounted has a thickness of 21 mm and a width of 12 mm, and both sides have a thickness of 24 m.
It was slightly inflated to m, width 14.5 mm. Face S
The weight without the gut was 260 g, and the balance point was 335 mm from the grip end. The racket frame had a hollow shape made of fiber reinforced resin, epoxy resin was used as the matrix resin, and carbon fiber was used as the reinforcing fiber. The dynamic damper was mounted so that the lengthwise direction of the vertical frame of the dynamic damper was parallel to the lengthwise direction of the racket frame.

(Example 1) Dynamic damper 10a
As the mass addition material 11, a heavy metal sheet manufactured by Sumitomo Electric Industries, Ltd. having a thickness of 0.6 mm was used. The specific gravity was 9 and the complex elastic modulus was 200 MPa. The structure of the heavy metal sheet was chloroprene rubber containing tungsten. Also, the dynamic damper 10
As the viscoelastic material 12 of a, a rubber having a composition shown in Table 1 below was used. The complex elastic modulus of the viscoelastic material 12 is 0.53.
It was MPa.

[0060]

[Table 1] In the table, M is 2-mercaptobenzothiazole, T
ET is tetrathiuram disulfide, BZ is dibutyl.
Dithioarbamine, TTTE, is tellurium diethyldithioarbamate.

The above mass-adding material 11 and the viscoelastic material 12 were laminated and charged into a mold, and pressed at 170 ° C. for 20 minutes,
Vulcanized The obtained dynamic damper 10a has a thickness of 4 mm, a width of 5 mm, and an aspect ratio of 0.38. As shown in FIGS. 8 (A) and 8 (B), the shape is two U-shaped horizontal frame portions. 13 has a lattice shape in which two strip-shaped vertical frame portions 14a are integrated. The distance between the U-shaped horizontal frame portions 13 is 5.
The length of the strip-shaped vertical frame portion 14a is 15 mm.
The length of the U-shaped lateral frame portion 13 was 5 mm, and the length was 41 mm. The dynamic damper 10a was adhesively fixed to the gut tension portion of the racket frame at the 3 o'clock and 9 o'clock positions, respectively.

(Example 2) Mass addition material 11 and viscoelastic material 1
The material and the manufacturing method of No. 2 are the same as those of Example 1, but the aspect ratio is 0.64, and the shape is the same as that of the above-described first embodiment. As shown in
The three U-shaped horizontal frame portions 13 are integrated with the two strip-shaped vertical frame portions 14 into a lattice shape. U-shaped horizontal frame 13
Is 5.5 mm, the length of the strip-shaped vertical frame portion 14 is 26 mm, and the length of the U-shaped horizontal frame portion 13 is 41 mm.
And The dynamic damper 10 was adhesively fixed to the gut tension portion of the racket frame at the 3 o'clock and 9 o'clock positions, respectively.

(Example 3) Mass addition material 11 and viscoelastic material 1
The material and manufacturing method of No. 2 are the same as those of Example 1, but the aspect ratio is 0.9, and the shape is four U-shaped horizontal as shown in FIGS. The frame portion 13 has a lattice shape in which it is integrated with two strip-shaped vertical frame portions 14b. The interval between the U-shaped horizontal frame portions 13 is 5.5 mm, the length of the strip-shaped vertical frame portions 14 b is 36.5 mm, and the U-shaped horizontal frame portion 13 is
Has a length of 41 mm. This dynamic damper 1
0b was adhesively fixed to the gut tension portion of the racket frame at the 3 o'clock and 9 o'clock positions, respectively.

(Embodiment 4) The dynamic damper 10 of Embodiment 2 was adhesively fixed to the racket frame at the gut tension portion 1 at 5 o'clock and 7 o'clock, respectively.

(Example 5) Mass addition material 11 and viscoelastic material 1
The material and manufacturing method of No. 2 are the same as those of the first embodiment.
As shown in 0 (A) and (B), the two U-shaped horizontal frame portions 23 and the two strip-shaped vertical frame portions 24 are separately positioned in a grid pattern to form the dynamic damper 20. did. The length of the strip-shaped vertical frame portion 24 is 15 mm, and the length of the U-shaped horizontal frame portion 23 is 41 mm, as shown in FIG.
As shown in (B), the racket frame f was adhesively fixed at the 3 o'clock and 9 o'clock positions on the gut tension portion.

(Example 6) Mass addition material 11 and viscoelastic material 1
The material and manufacturing method of No. 2 were the same as those in Example 1, but the heavy metal sheet had a thickness of 1.0 mm in addition to 0.6 mm as in Example 1. Thickness is 1.
When a 0 mm heavy metal sheet was used, the thickness of the viscoelastic material was 3.5 mm, the total thickness of the dynamic damper was 4 mm, and the amount of oil was 200 parts by weight in the rubber composition of the viscoelastic material. Two strip-shaped vertical frame portions 34 ′ having a thickness of the heavy metal sheet of 0.6 mm and two strip-shaped vertical frame portions 34 having a thickness of the heavy metal sheet of 1.0 mm are shown in FIG. ) As shown in (B),
3 o'clock and 9 o'clock on the gut tension of the racket frame f, respectively.
Two dynamic adhesives 30 were bonded and fixed to each position at the time to form a dynamic damper 30. The length of the vertical frame portions 34, 34 'is 26 m.
m.

(Example 7) Mass addition material 11 and viscoelastic material 1
The material and manufacturing method of No. 2 are the same as in Example 1, but the aspect ratio is 0.29, and the shape is two U-shaped horizontal as shown in FIGS. 13 (A) and (B). The frame portion 13 has a lattice shape in which two frame-shaped vertical frame portions 14c are integrated. The distance between the U-shaped horizontal frame portions 13 was 2 mm, the length of the strip-shaped vertical frame portions 14 c was 12 mm, and the length of the U-shaped horizontal frame portions 13 was 41 mm. This dynamic damper 10c
Were bonded and fixed at the 3 o'clock and 9 o'clock positions on the gut tension portion of the racket frame, respectively.

(Comparative Example 1) Mass addition material 11 and viscoelastic material 1
The material and manufacturing method of No. 2 are the same as those of the first embodiment, but only the dynamic damper 40 composed of three U-shaped bodies 43 is used as shown in FIGS. 14 (A) and (B). The length direction of 43 was perpendicular to the longitudinal direction of the racket frame, and at intervals of substantially parallel to each other, the gut tension portion of the racket frame was adhesively fixed at the 3 o'clock and 9 o'clock positions. Each U-shaped body 43 was mounted between the gut insertion hole and the gut insertion hole. The length of the U-shaped body 43 is 41
mm.

(Comparative Example 2) Mass addition material 11 and viscoelastic material 1
The material and manufacturing method of No. 2 are the same as those of the first embodiment, but only the dynamic damper 50 composed of two strip-shaped bodies 54 is used as shown in FIGS. 15 (A) and 15 (B). The racket frame is placed substantially parallel to each other in the width direction so that the length direction is parallel to the longitudinal direction of the racket.
It was adhesively fixed at the 3 o'clock and 9 o'clock positions on the gut tension section of f.
The length of the strip-shaped body 54 was 26 mm.

(Comparative Example 3) The materials for the mass addition material 11 and the viscoelastic material 12 and the manufacturing method are the same as in Example 1, but the aspect ratio is 1.16, and the shape is as shown in FIG. As shown in B), five U-shaped horizontal frame portions 63 are integrated with two strip-shaped vertical frame portions 64 to form a lattice shape. The interval between the U-shaped horizontal frame portions 63 was 5.5 mm, the length of the strip-shaped vertical frame portions 64 was 47 mm, and the length of the U-shaped horizontal frame portions 63 was 41 mm. This dynamic damper 60
Were bonded and fixed at the 3 o'clock and 9 o'clock positions on the gut tension portion of the racket frame, respectively.

With respect to the tennis rackets of Examples 1 to 7 and Comparative Examples 1 to 3, out-of-plane secondary and in-plane tertiary frequencies and damping ratios were measured, and the tennis racket vibrations were measured. Was evaluated.

(Measurement of Frequency and Damping Ratio) A method for measuring the natural frequency of the tennis racket TR and its damping ratio is shown in FIG.
And shown in FIG. For accurate measurement, the acceleration pickup 73 is attached at the maximum vibration width position of each vibration mode, and the impact hammer 71 is similarly set at the maximum amplitude position.
I was excited by. The gut stretched portion of the racket frame f was not stretched with the gut, and the measurement was performed by the free support method in which the string was suspended as shown in FIG. 19 or FIG. Impact hammer 7
The input vibration (F) measured by the force pickup attached to No. 1 and the response vibration (α) measured by the acceleration pickup 73 are transmitted through the amplifiers 72 and 70 to the frequency analysis device 7
4 (manufactured by Hewlett-Packard, Dimic Signal Analyzer HP3562A). This is an evaluation method assuming that the rigidity of the racket frame f is linear.

The transfer function in the frequency domain was obtained by the above analysis, and the out-of-plane secondary frequency and the in-plane tertiary frequency of the racket frame were obtained. The damping ratio (ζ) was calculated from FIG. 18 by the following mathematical formula.

Ζ = (1/2) × (Δω / ωn) To = Tn / √2

The out-of-plane secondary frequency is the second peak from the low frequency when the tennis racket TR is set in a freely supported state in which it is suspended by a string as shown in FIG. When a vibration (deformation) of an out-of-plane secondary mode occurs in the unvibrated (before deformation) tennis racket TR of FIG. 21A (side view of the tennis racket) as shown in FIG. 21B. Frequency. The in-plane third-order frequency is the third peak from the low frequency when the tennis racket TR is set in a freely supported state in which the tennis racket TR is suspended by a string as shown in FIG. A) unvibrated (before deformation) tennis racket TR
In addition, as shown in FIG. 22B, it is the frequency when the vibration (deformation) of the in-plane third-order mode occurs.

(Evaluation on Vibration) The above Examples 1 to 7 and Comparative Examples 1 to 3 were given to 30 intermediate and advanced players.
We asked the player to hit the ball with the tennis racket and evaluated the degree of vibration at the time of hitting the ball with a maximum of 5 points. The one with the least vibration is "5", and the one with the most vibration is "1"
And The average value of 30 persons was calculated and used as the evaluation value.

Table 2 below shows the shapes of the dynamic dampers of Examples 1 to 7 and Comparative Examples 1 to 3, the aspect ratio of the lattice, the position of attachment to the racket, the weight of the dynamic damper, the respective measurements, and the evaluation results.

[0078]

[Table 2]

As shown in Table 2, in Examples 1 to 7, both the out-of-plane second-order and the in-plane third-order attenuation ratios are 1% or more. Particularly, the out-of-plane secondary and in-plane of Examples 2, 3 and 4 which are integrally formed in a lattice shape and have an aspect ratio of 0.6 or more and 0.9 or less and are adhesively fixed at the positions of 3:00 and 9:00, respectively. The third-order damping ratio was a very large value as compared with the others, the vibration damping property was particularly excellent, and the evaluation points regarding vibration were also very good results.

On the other hand, Comparative Example 1 is a case of a dynamic damper having a U-shape and only in the lateral direction. The in-plane third-order damping ratio was 1% or more, but the out-of-plane second-order damping ratio was It was low. Comparative Example 2 is a strip-shaped dynamic damper in the vertical direction only. On the contrary, the out-of-plane secondary damping ratio was 1% or more, but the in-plane tertiary damping ratio was low. .
In Comparative Example 3, the aspect ratio was 1.16 and the in-plane third-order damping ratio was low. This is because the aspect ratio greatly exceeds 1, which makes it difficult for the damper to swing, particularly in the in-plane direction. In this way, in the case of a dynamic damper that has only a U-shape or a strip shape and does not have portions that resonate in both in-plane and out-of-plane directions, effectively suppresses both out-of-plane and in-plane vibration. I couldn't.

As described above, as in the embodiment, the dynamic damper in which the U-shaped horizontal frame portion and the strip-shaped vertical frame portion are integrally or separately arranged in a lattice pattern is used. It was confirmed that the vibration damping property in both directions was excellent.

[0082]

As is apparent from the above description, according to the present invention, the shape of the dynamic damper is a lattice shape in which the vertical frame portion and the horizontal frame portion are integrally formed or separate members are joined to each other. Since the vertical frame part resonates mainly with out-of-plane vibrations, the horizontal frame part mainly resonates with in-plane vibrations, effectively suppressing vibration in both directions. be able to.

Further, in the case of integrally forming in a lattice shape, since the vertical frame portion is connected to the horizontal frame portion, the whole lattice resonates together with the in-plane vibration, so that the in-plane vibration is suppressed. The effect is better. That is, when integrally molded in a lattice shape, the weight of the entire dynamic damper contributes to suppressing vibration in the in-plane direction and the out-of-plane direction, so that the vertical frame portion and the horizontal frame portion individually move in the in-plane direction and the out-of-plane direction. It is more excellent because the vibration suppressing effect is increased rather than contributing to the vibration suppressing.

Furthermore, when the dynamic damper of the present invention is attached to a tennis racket, both in-plane and out-of-plane vibrations can be suppressed more efficiently without adversely affecting the operability of the tennis racket. The out-of-plane secondary and in-plane tertiary damping ratios are both 1% or more. Therefore, the unpleasant feel at impact can be eliminated, and the effect of suppressing the rotation of the racket when the ball hits other than the center of the face surface can also be achieved, and the burden on the elbow etc. of the tennis racket user is also reduced. can do.

Particularly, the positions of the racket frame at 3 o'clock and 9 o'clock are the maximum vibration width position of the in-plane vibration and the maximum vibration width position of the out-of-plane secondary vibration. When the dynamic damper of the present invention is attached to the time position, both in-plane and out-of-plane vibrations are suppressed,
Moreover, the impact due to the rotation of the grip can be suppressed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a dynamic damper according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which the dynamic damper according to the embodiment of the present invention is attached to a racket frame.

FIG. 3A is a front view, FIG. 3B is a side view, and FIG. 3C is a plan view of a dynamic damper according to an embodiment of the present invention.

FIG. 4 is a plan view showing a state in which the dynamic damper according to the embodiment of the present invention is attached to the racket frame at the 3 o'clock and 9 o'clock positions.

FIG. 5 is a plan view showing a mounting position of the dynamic damper of the embodiment of the present invention to the racket frame.

FIG. 6 is a plan view showing a state in which the dynamic damper according to the embodiment of the present invention is attached to the racket frame at the 4 o'clock and 8 o'clock positions.

FIG. 7 is a plan view showing a state in which the dynamic damper according to the embodiment of the present invention is attached to the racket frame at the 5 o'clock and 7 o'clock positions.

FIG. 8A is a front view and FIG. 8B is a side view of the dynamic damper of the first embodiment.

9 (A) is a front view and FIG. 9 (B) is a side view of a dynamic damper of Embodiment 3. FIG.

10A and 10B are schematic diagrams of a dynamic damper according to a fifth embodiment.

FIG. 11 is a schematic view showing a state in which the dynamic damper of the fifth embodiment is attached to the racket frame, (A) is a front view, and (B) is a view from the inside of the racket frame.

FIG. 12 is a schematic view showing a state in which the dynamic damper of the sixth embodiment is attached to the racket frame, (A) is a front view, and (B) is a view from the inside of the racket frame.

FIG. 13 (A) of a dynamic damper of Example 7.
Is a front view and (B) is a side view.

FIG. 14 (A) of a dynamic damper of Comparative Example 1
Is a front view and (B) is a plan view.

FIG. 15 (A) of a dynamic damper of Comparative Example 2
Is a front view, and (B) is a side view showing a state of being attached to a racket frame.

FIG. 16 (A) of a dynamic damper of Comparative Example 3
Is a front view and (B) is a side view.

FIG. 17 is a block diagram showing a measurement system of frequency and damping ratio.

FIG. 18 is a graph showing the relationship between the frequency and the transfer function in the analysis by the measurement system of the frequency and the damping ratio.

FIG. 19 is a schematic diagram showing a measurement position for vibration in an out-of-plane secondary mode.

FIG. 20 is a schematic diagram showing a measurement position for vibration of an in-plane third-order mode.

21 (A) and (B) are out-of-plane 2 of a tennis racket.
It is a schematic diagram explaining the vibration of the next mode.

22 (A) and (B) are in-plane 3 of the tennis racket.
It is a schematic diagram explaining the vibration of the next mode.

FIG. 23 is a diagram showing a conventional example.

FIG. 24 is a drawing showing another conventional example.

FIG. 25 is a view showing another conventional example.

[Explanation of symbols]

1 Gut tension section 10 Dynamic damper 11 Mass addition material 12 Viscoelastic material 13 Horizontal frame 14 Vertical frame TR tennis racket f racket frame g gut S face side

Claims (5)

(57) [Claims] 1. A dynamic damper, which is formed by integrally laminating a viscoelastic material and a mass addition material and is attached to a racket, the grid including a horizontal frame portion and vertical frame portions on both sides of the horizontal frame portion. In the shape, the horizontal frame portion and the vertical frame portion are integrally provided or joined separately, and the horizontal frame portion is attached to at least one surface in the thickness direction of the racket, and the vertical frame portion is the racket. A dynamic damper characterized by being attached to both sides in the width direction of the. 2. The horizontal frame portion is bent into a U-shape, the ends of both side bending portions are integrally or joined to the vertical frame portion, and both side bending portions of the horizontal frame portion are attached to both sides in the width direction of the racket. The dynamic damper according to claim 1, wherein 3. The dynamic damper according to claim 1, wherein there are two or more horizontal frame portions, and the horizontal frame portions are arranged so as to sandwich the gut insertion hole. 4. The ratio (L2 / L1) of the length (L2) of the vertical frame portion to the length (L1) of the horizontal frame portion is 0.3 or more and 1.0 or less, and each portion of the viscoelastic material. Has a width of 4 mm or more and 8 mm or less, and the thickness of each part of the viscoelastic material is 2.5 mm or more and 5.5 m
The dynamic damper according to claim 1, wherein the dynamic damper has a total weight of 8 g or more and 23 g or less. 5. The complex elastic modulus of the viscoelastic material at 20 ° C. and 10 Hz is 0.3 MPa or more and 1.5 MPa or less, and the complex elastic modulus of the mass addition material at 20 ° C. and 10 Hz is 1.
The dynamic damper according to any one of claims 1 to 4, which has a pressure of not less than 00 MPa and not more than 800 MPa.